The present invention relates generally to the field of electronic article surveillance, and in particular, to a system for deactivating the field-sensitive tags or labels which are used in conjunction with such electronic article surveillance systems.
For enhanced security and inventory control, it is becoming increasingly popular for various types of establishments to employ electronic article surveillance systems. Numerous systems have been proposed to accommodate these various applications. However, irrespective of the application involved, such electronic article surveillance systems generally operate upon a common principle. Articles to be monitored are provided with tags or labels (of various different types) which contain a circuit (e.g., a resonant circuit) for reacting with an applied (e.g., radio-frequency) field. A transmitter and a transmitting antenna are provided to develop this applied field, and a receiver and a receiving antenna are provided to detect disturbances in the applied field. If the field-sensitive circuit of a tag is passed between the transmitting and receiving antennas (positioned at the desired verification point), the applied field is affected in such fashion that a detectable event is produced within the receiver. This is then used to produce an appropriate signal, or alarm. Systems of this general type are available from manufactures such as Checkpoint Systems, Inc. of Thorofare, N.J., among others.
The tag (or label) which is used in conjunction with such systems is generally provided with an internally disposed stimulus which is capable of exciting the associated apparatus. This often takes the form of a circuit which is capable of reacting with a specified field to cause the detectable event which is used to provide a warning signal. An example of a tag of this general type, which is useful in connection with an applied radio-frequency field, may be found in U.S. Pat. Nos. 4,567,473 and 4,498,076.
It is presently common practice to manufacture such tags in a fashion which makes them as universal as possible, permitting the tags to receive different markings and to be applied to different types of articles without necessitating the use of a large number of different types of tags for this purpose. This assists in reducing costs, and enhances convenience for the end user. However, it has been found that there are certain applications, involving certain types of articles to be marked, where more specialized tags would be useful.
One such application involves the retail sale of footwear, primarily shoes and the like. It has recently become increasingly popular to sell shoes in retail establishments which are essentially "self-service", eliminating the need for specialized personnel and accordingly reducing the costs of operating an establishment of this type. This necessitates the placement of a large number of shoes in an unattended area, for free consumer access. However, this has the corresponding disadvantage of facilitating the removal of goods from the retail establishment, without having first paid for them. It has therefore become desirable to develop a field-sensitive tag which is especially suited to applications of this general type, and the special problems which such applications present.